Microsoft delivered the latest version of its unified communications platform on Tuesday, a release that makes progress towards its goal of integrating telephony and instant messaging (IM) features on the same commodity servers.

The software titan unveiled Office Communications Server 2007 Release 2 (R2) in mid-October at the VoiceCon conference in Amsterdam, saying at the time that it would be ready for sale this month.

However, despite an on-time arrival, there's plenty of work that remains to be done.

Unified communications aims to tie instant messaging, e-mail, Voice over Internet Protocol (VoIP) , and presence technology, as well as video and Web conference capabilities into a single platform strategy.

"This new release puts Microsoft (NASDAQ: MSFT) on a rapid path to deliver voice software that does much more than a network private branch exchange (PBX) and with much less cost," Stephen Elop, president of the Microsoft Business Division, said in a statement.

Microsoft's pitch to the enterprise is that they use OCS for instant messaging and collaboration, and continue to amortize the investment in their existing PBX systems. OCS can integrate with those legacy systems, in some cases enabling employees to have incoming calls routed simultaneously to both their VoIP and landlines.

Midlife crisis?

Still, OCS 2007 R2 poses a bit of a conundrum for analysts. Is it an incremental step in the right direction to achieve unified communications, or the mid-point in a radical makeover from a corporate IM solution to PBX replacement?

Office Communications Server 2007 adds VoIP to the IM and collaboration features the company had previously marketed as Live Communications Server. The name was changed to OCS in 2007.

"OCS R2 is, first and foremost, a corporate IM system that is moving to make it into a VoIP server," Brian Riggs, research manager at Current Analysis, told InternetNews.com. His feeling is that R2 is a mid-point in the migration to merging voice and messaging in the same box.

"They're trying to get their customers ready for transitioning from a traditional PBX environment to using OCS as their one and only voice platform," Riggs added.

Nick Lippis, publisher of the Lippis Report takes a slightly more cynical view. "I still walk away and say 'That's great, but they've got a long way to go'," Lippis said.

That doesn't mean that he's completely cold on R2, though.

"What they've done in R2 is added some of the major building blocks that will allow OCS to scale, to plug-in to PSTN (public switched telephone networks), and to provide SIP (session initiation protocol) trunking that can reduce a lot of WAN costs," Lippis said.

What it adds up to is an ongoing assault on PBX makers.

"There are dynamics in the PBX market that are playing into Microsoft's hands," Riggs said.

The PBX makers have been moving to servers running Linux and Windows, making a transition to OCS that much simpler since they use the same hardware.

"I think it's becoming completely clear that Microsoft is going to perform a long-term role in the unified communications market," Riggs added.

Lippis still isn't convinced.

"They still haven't proven large-scale deployments  you can't look around the industry and see many 10,000 person installations . Microsoft is new to this space so it's going to take some time to get there," Lippis added.